I think your test result is quite good.For image B, C, D is really nice.A :Good leveling and it's nice you clean & redraw the watermark.RAW for image A is rather small, therefore when you want to resize it into a bigger RAW, you need to filter it first.You can use Topaz Denoise and Topaz Clean (free plug-ins for Adobe Photoshop) or just simply use Filter > Smart Blur (usually use 2-3 px).E1 & 2 :It's over leveled. You can reduce the white & black leveling. When you do that there will be some noise left. You can use magic wand to select the bigger area and start brushing with white brush. With magic wand it will be easier when cleaning the noise.